1. Field of the Invention
The present invention relates to a structure and method for attaching tactile sensors to a curved surface and, more particularly, to a structure and method for attaching a curved surface type tactile sensor, wherein the tactile sensor is inserted into a sensor fixing unit having sensor insertion grooves formed in a concave or convex curved surface, thereby enabling the tactile sensor to be easily attached to the curved surface and enabling mass production.
2. Background of the Related Art
A tactile function for obtaining pieces of information (i.e., the intensity of contact force, vibration, surface roughness, and a temperature change of thermal conductivity) about surrounding environments through a contact is being understood as the next-generation information gathering medium. A bio-mimetic tactile sensor replaceable with a tactile sense becomes more important because it may be used in a variety of medical diagnoses and operations, such as a micro operation within a blood vessel and a cancer diagnosis and applied to tactile sensation proposal technology important in the future virtual environment implementation technology.
The bio-mimetic tactile sensor is for a force/torque sensor of 6 degrees of freedom which is already used in the wrist of an industrial robot and the gripper of a robot and is configured to detect contact pressure and instant sliding, but is problematic in that it has a low sensitivity owing to a relatively bulky detection unit.
FIG. 1 is a conceptual diagram of an artificial skin attached to a two-dimensional curved surface, and FIG. 2 is a conceptual diagram of an artificial skin attached to a three-dimensional curved surface. In order to give a tactile sensation to a machine, artificial skins 11 and 21 may be implemented by attaching a bio-mimetic tactile sensor. The conventional tactile sensor is formed of a flat film and may be attached to an object 10 having a two-dimensional curved surface, such as that shown in FIG. 1, but may not be attached to an object 20 having a three-dimensional curved surface, such as that shown in FIG. 2. Accordingly, there is a need for a flexible tactile sensor.
There is a possibility that the tactile sensor may be developed using Micro-ElectroMechanical Systems (MEMS) technology. However, this technology is problematic in that the tactile sensor does not have flexibility because a sensor is formed using a silicon wafer.
FIG. 3 is an explanatory diagram showing an example of a conventional tactile sensor. The conventional tactile sensor of FIG. 3 was made public by a Takao Someya group in the University of Tokyo in 2005. In accordance with this technology, a tactile sensor 31 was formed of a single film through a punching process, thereby partially implementing flexibility and extensibility. Accordingly, the tactile sensor 31 can also be attached to a globular shape 30. The tactile sensor 31 fabricated by the punching process, however, does not have the greatest flexibility because a sheet of a film is punched in order to give flexibility. Accordingly, the tactile sensor 31 may be applied to a globular shape having a large cylinder or a large curvature, but has a problem in that it may not be applied to an organ, such as a finger of a human type robot, or a very small globular shape because it lacks soft like a human skin. Furthermore, there are problems in that automation is difficult and an individual manual work is necessary because the tactile sensor 31 must be attached one by one.
FIG. 4 is a perspective view showing another example of a conventional tactile sensor. The conventional tactile sensor of FIG. 4 was made public by a Wagner group of Princeton University in 2005. A tactile sensor 41 according to this technology includes metal lines 41b formed on a polydimethylsiloxane (PDMS) substrate 41a and a fixing cell 41c formed at a crossing of the metal lines 41b. The tactile sensor 41, however, is problematic in that a crack is generated in the metal line 41b if peeling is generated between the metal lines 41b and the substrate 41a or if slight deformation occurs and the tactile sensor 41 is worn by a continuous contact.
Someya, T., Kato, Y., Sekitani, T., Iba, S., Noguchi, Y., Murase, Y., Kawaguchi, H. and Sakurai, T., “Conformable, flexible, large-area networks of pressure and thermal sensors with organic transistor active matrixes,” Proc. National Academy of Sciences of USA, Vol. 102, No. 35, pp. 12321-12325, 2005.